The agency has also registered a case against 20 unknown persons under charges of criminal conspiracy, murder, attempt to murder and criminal intimidation.

After demands were raised for a CBI probe in the deadly accident that took place on Sunday, the probe agency has finally registered the case.

The CBI team has already collected the relevant case documents and other details from the UP police.

The team will start its probe by visiting the crime scene today. The agency has also alerted its officials, who may visit the accident site and take details from police officials of Gurubakshganj Police Station in Rae Bareli where the accident took place.

The move comes after the Centre on Tuesday handed over the probe into the truck-car collision that left the Unnao rape victim critically injured over to the CBI.

An order from the Department of Personnel and Training said the case is being handed over to the agency to probe "abetment and conspiracies" in the accident.

On Sunday, the car in which the rape survivor, her family and lawyer were travelling was hit by an overspeeding truck in Rae Bareli, killing two members and leaving her and the advocate critically injured.

The Uttar Pradesh Police on Monday filed a murder case against Sengar and nine others after the rape survivor's family filed a complaint, alleging conspiracy behind the accident.

What does the FIR say?

The FIR was filed on a complaint given by the survivor's uncle, who is currently lodged in a jail in Rae Bareli.

The complainant has alleged that Sengar's men used to threaten his family to withdraw the rape case against the MLA, else they will be killed.

"My family members told me that MLA Kuldeep Singh used to call his men in the Makhi village from the phone of one Simple Mishra and threaten my family. He used to say that if you want to live, change the statements you gave in court," the complainant alleged.

He claimed that the threatening calls were made in the presence of police officers.

He said that Sengar, 10 others, as well as 15-20 unidentified men, used to tell his family to reach a compromise with Sengar else they will be killed.

The complainant, who is in jail on multiple charges, also alleged that the accused told his family to stop meeting him as they had made "a program" to keep him in jail.

"They said when he [the uncle] is released from jail in 10-15 years, we will end him also," he added.

The survivor's uncle has also alleged that Sengar was being shielded by the BJP government. He has also alleged the police asked them to give in to the threats made by Sengar's men.

In his complaint, he has said, "When I used to appear in courts, the accused persons would say that the government is standing with the MLA...my wife showed video evidence of the threats to the police, they said he is a BJP MLA and is still in the party. The police officers said we have to do our jobs so it is best that you listen to what these people are saying."